The present invention relates to control systems for use in systems which supply power to more than one load. In particular, the present invention is a control system which provides programmed priority to one of the loads and allows the other load to use the remaining available power.
There are many systems in which power is supplied to more than one high power consuming load. One example of such a system is a photographic processor, which includes solution tanks for developing photographic film or paper and a dryer for drying the film or paper. Heaters are required to heat the solution used in the solution tanks and to heat air used in the dryer.
An additional requirement of the photographic processor is that the developer solution and the drying air must be heated rather rapidly. This causes the solution heater and dryer heater to have very high peak power demands (the developer during initial warm up and the dryer when processing). The power required to maintain the solution at the desired temperature once that temperature has been initially attained is much less than the power required for fast heat up. For example, the power required to maintain solution temperature is typically less than 50% of the peak power required for fast heat up.
The separate high peak power demands of the solution and dryer heaters create several significant problems. First, the high demand is expensive to the owner/operator of the processor. Second, the high demand may require special electrical wiring or special electrical service in order to provide the necessary power. This is an additional expense and complication which should be avoided if possible.